Parker 950 Door Closer

I have a S Parker 950 door closer that is closing ok until it gets to the last couple of inches and then slams. There are two adjustments on the body, on the left and right side. I called Parker and the person I spoke to really had no idea what to do.

I tried turning the right side (when in front of it) screw and it slows the door closing but does nothing for the last few inches.

I then tried the right screw and that didn't seem to do anything at all but it may be me.

Any help understanding the magic of how this thing works and how to adjust it will be greatly appreciated.

 

Not familiar with the model you have, but most surface closers with one screw on each end means one screw ("Backcheck") cushions the full-open door position, and the other screw is dual purpose: Speed of the "Sweep" (full open to a few inches before closed) and "Latching" speed (last few inches). As you have discovered, the Sweep speed is a course adjustment and may require a full turn or more to affect a noticeable change. However, the Latching speed is very sensitive to adjust, and one revolution of the screw will pass through 2 complete fast/slow cycles.

If you're happy with the Sweep speed, slowly adjust the screw (either way) in no more than 1/8 turn at a time, until you notice the Latching speed come almost to a stop. At that point, make very tiny adjustments until you have it to your liking.